The objective during the award period is to develop the candidate's knowledge and investigative skills in membrane biology and cellular electrophysiology. The subject for study will be the coronary artery smooth muscle cell whose contractile and proliferative responses to numerous humoral and therapeutic agents have given it a pivotal role in vascular and myocardial pathophysiology. Under the sponsorship of Dr. Thomas W. Smith and the preceptorship of Dr. David E. Clapham, the candidate will focus his experimental program on the isolated cell preparation of bovine coronary artery smooth muscle and the electrophysiology of its calcium channels, which are known to mediate such important responses as muscle contraction and exocytosis. In Phase I, cell isolation procedures will be refined in order to produce optimal cells expressing native physiology. The patch clamp technique of Neher and Sakmann will be used to characterize the basal behavior of the calcium channel(s) by their voltage-dependence, kinetics, and their response to transmitters and antagonists as measured in whole-cell and single-channel recordings. In addition, during Phase I, formal coursework in cell and membrane biology and electrophysiology at Harvard Medical School will broaden and strengthen the candidate's working knowledge of his investigations. In Phase II, the modulation of calcium channel behavior by transmitters, hormones, growth factors and therapeutic agents will be studied by means of controlled perfusion of the intracellular and extracellular membrane surfaces with the agent under study. In addition, the effects of intracellular agents, such as modifiers and components of the adenylate cyclase and phosphatidyl inositol second messenger pathways, on calcium channel activity will be studied. Through a coherent program of intensive research and coordinated didactic learning, the award would allow the candidate to gain the knowledge and experience to become an independent, productive investigator in the membrane biology and cellular electrophysiology of cardiovascular science.